Data privacy is an important issue for online users. Users often have to reveal their personal or sensitive information, such as names, addresses, emails, credit card numbers, login information, etc., to various online service providers when they participate in various online activities, such as online banking, online shopping, or even simply logging in to a social networking website. A user's personal information, once provided to a service provider, then may be used for purposes different from the original intention of the user for revealing that information. By way of example, the advertising industry is particularly keen to use personal information for targeted marketing. In view of the increasing concerns of data privacy, various privacy laws in many countries have emerged to prevent such personal information from misuse and may require whoever collects personal information to respect certain rights of the user.
However, online users generally lack the ability to control the personal information that they have exposed over the Internet. As an example, over time, a user can easily lose track of what personal information the user has provided to which service provider. Further, users lack an effective means to recall their personal information from a service provider, or in general, to manage their personal information distributed among various service providers. Further still, users are often required to repeatedly input the same personal information for new service providers, which can be tedious and error-prone for data entry, especially with small mobile computing devices, and risks exposing the user's sensitive information to abuse.